Floor underlayment



FIG. 1 is a top perspective view of a floor underlayment showing my new design;

FIG. 2 is a side elevation view of FIG. 1, the other side elevation views being identical thereof;

FIG. 3 is a top plan view of FIG. 1;

FIG. 4 is a bottom plan view, opposite that of FIG. 3; and,

FIG. 5 is a bottom perspective view, opposite that of FIG. 1. 

CLAIM The ornamental design for a floor underlayment, as shown and described. 